The following accident was investigated by Doug Fesler and Jill Fredston of the Alaska Mountain Safety Center, Inc. The results of their investigation appear here with minimal editing.
WEATHER AND SNOWPACK CONDITIONS
In the fall of 1998, snowfall in the Turnagain Pass area of Alaska began in early October and continued for much of the month. The snowpack was sufficiently deep for winter recreation by late October. The snowpack maintained a normal depth into January of 1999. Then, during late January and early February, a dry and very cold spell brought minimum temperatures of -10 to -30 ̊F. This created a widespread layer of facets and surface hoar that became a buried weak layer when snowfall resumed toward the end of February. Snow fell almost daily from late February through March 20.
March 21 dawned clear, warm, and windless. As temperatures rose through the day, avalanche potential also rose. Observant drivers on the Seward Highway coming from Anchorage would have noticed numerous fresh avalanches on the mountain slopes visible from the highway.
Turnagain Pass, at 900 feet elevation, is the high point on the Anchorage-to-Seward Highway. The slopes of the Kenai Mountains that surround the pass provide extensive opportunities for winter recreation. Snowmobilers are restricted to the west side of the highway, while the east is set aside for backcountry skiers and snowboarders. On Sun- day, March 21, the parking area was jammed to capacity with 100 to 150 snowmobiles, with overflow parking lining the sides of the highway.
Three significant avalanches released in the two hours prior to the fatal avalanche. At about 14:00, a natural avalanche released on the east face of Pyramid Peak, about two miles to the north, out of view of almost all the snowmobilers. At about 14:30, a second natural avalanche released in an area called the Knob, which is a natural ramp that snowmobilers use to access the western ridge that overlooks Turnagain Pass to the east and Seattle Creek to the west. This area is also to the north of where the fatal avalanche would occur, and it was a close call for two snowmobilers. Brent Snow and his wife were at the base of the path when it released. Unable to get his machine started, Snow jumped on his wife’s machine. As they sped out of the runout zone, the powder cloud dusted them with snow. They escaped unharmed. When they returned for Snow’s machine, they found it partly buried by debris at the toe of the slide. This slide was large—four to six feet deep by a half-mile wide—and was also observed by several skiers on the east side of the valley.
Unfortunately, few of the other snowmobilers in the area observed or heard about these two slides, or if they did, they failed to recognize the importance of the message.
The third avalanche released at about 15:45, about a half-mile to the south of the Knob. It may have released naturally or been triggered by riders nearby. In either case, no one was caught.
Several riders closely observed this last slide. They had been highmarking. Moments later, this group of riders gathered near the runout of the most recent slide to talk over what they should do. Three members of this group were Ken Seagle, Dan Demers (37), and Aaron Arthur (29). They talked about the hazard and decided they had better “pack it in”—but first they wanted to make one more climb. The time was 16:00 when they started up the large slope that lay to the south of the Knob and to the north of the third avalanche that had run 15 minutes before.
What followed was pure chaos—ride-for-your-life chaos.
Seagle, Demers, Arthur, and a fourth rider were climbing, and numerous other riders were also on the slope when it fractured. The fracture line propagated half a mile across the top of the slope, and it was six feet deep. Ken Seagle was climbing the rider’s left (south) side of the slope, which also was along the edge of the last avalanche from 15 minutes earlier. He was halfway up when he looked over his shoulder and saw the whole mountain to the north avalanching. He turned his machine to the left and rocketed toward the debris of the earlier slide and was successful in escaping onto the pile of snow blocks that were four to five feet in size. At 50 mph, he was airborne more than in contact with the snow.
To Seagle’s right (north) and about halfway up the mountain was Dan Demers, who had gotten his snowmobile stuck and was helpless when the avalanche broke above him. He and his sled were tumbled about 1,700 feet slope distance (500 feet vertical) down the mountainside. Seagle could see Demers’ snowmobile, which was partly bur- ied but totally destroyed. Seagle rode to the area to search. A man with a probe joined him a few minutes later and began probing in the area of the snowmobile. He eventu- ally struck Demers, about five feet uphill from his snowmobile. Demers’ head was 5.5 feet beneath the surface, and it took several more minutes to dig him out. Demers had been buried for about 40 minutes. He did not respond to CPR administered by a nurse who happened to be on the scene.
Aaron Arthur was in the process of making a long traverse from south to north and was about three-quarters of the way up the north side of the slope. He had just entered a very steep section of snow—later measured at 48 to 50 degrees—when the avalanche fractured about 300 feet above him. Witnesses quickly lost sight of Arthur and his snowmobile as they were carried downslope. Later in the day, Arthur’s snowmobile was found 600 feet vertical below its last-seen point, but rescuers could not find Arthur.
Four men—Ray and Rex Richards, Fred Maranville and Steve Estes—were watching Arthur from their vantage point at the top of the Knob. They realized the avalanche was going to overrun their location. The Richards brothers and Maranville managed to get their machines started and sped off as the slide bore down on them. Estes, unable to start his machine, opted instead to run north toward some nearby mountain hem- locks. The powder blast hit him almost immediately. With a vise grip on a tree, he was able to hold on and was only dusted by the passing powder cloud.
The other three, Ray and Rex Richards and Fred Maranville, powered over the southern edge of the Knob and were hit by the avalanche almost immediately. They were knocked off their snowmobiles and violently tumbled about 600 vertical feet down the mountainside. When the snow came to a stop, Ray lay dazed on the surface, suffering from a concussion and facial cuts. He was four feet downslope from his bro- ken snowmobile which was lying on its side, skis pointing uphill.
Ray remembered seeing a snowmobile hurtling through the air just before being
hit by the slide. It may have been Fred Maranville’s machine. Maranville came to rest 30 to 40 feet above Ray, but he was underneath his overturned snowmobile. He had a badly injured leg but managed to crawl out and establish contact with the others. Rex Richards and his machine ended up 50 to 60 feet below Ray, but were out of sight below a mound of avalanche debris. Rex had suffered a broken nose and lacerated face. His snowmobile had landed upside down with only its ski tips showing. Broken glass, anti-freeze, and blood covered the snow. Ray, Rex, and Fred were extremely lucky not to have been killed.
The avalanche continued its downward rush and slammed into other groups lower on the slope. Victor Jones (37) had been idling below the Knob on the north side of the slope when the avalanche hit him. The force carried him and his snowmobile 1,700 feet slope distance and completely buried both. It wasn’t until Wednesday, three days later, that rescuers recovered his body from under seven feet of snow.
Jones’ riding partner, Ray Debor (35), was approximately 150 feet downslope from Jones, heading downhill, when he was hit from behind. Debor never knew the slide
was coming. He and his snowmobile were carried to within 70 feet of the toe of the slide where his machine was buried to the windshield while Debor was still sitting on the seat, buried to his knees and uninjured. There were two other two members of this group: Shane Brown, (25) and Brian Kirk (24). They were at the bottom of the slope, roughly 150 feet below Debor. When they saw the slide coming, they had time to drive to safety and were merely dusted by the powder cloud.
Two other men, Chris Scott (24) and Jodi Combs (26) were riding together in the lower portion of the slope when they were hit and knocked off their snowmobiles. Scott’s snowmobile came to rest with its handlebars and seat out of the snow, but there was no sign of Scott. Similarly, Combs was knocked off his machine and completely buried as well. Sunday evening, rescuers recovered Scott’s body from under seven feet of snow. He had been buried 18 feet from his snowmobile. Monday afternoon, rescuers found Combs’ body also under seven feet of snow, but he was separated from his snowmobile by 132 feet.
The sixth and final deceased victim was Jeff Saunders (29). His whereabouts at the time of the avalanche was not known, but rescuers found his body seven feet deep and about 50 feet from his snowmobile.
Evidence indicates that the avalanche was quite turbulent right to the end of the runout zone. Jeff Piakowsky (17) shot a video of the avalanche from Tincan Ridge, on the other side of the highway. It shows six to eight other snowmobilers fleeing the slide. The total number of victims caught and the number of close escapes will never be known.
Immediately after the dust settled, witnesses responded from all directions and came into several areas of the avalanche debris zone. Additionally, numerous 911 calls were made to alert rescue authorities. The debris covered an area that was roughly half a mile by a quarter mile, with debris typically deeper than 10 feet. For the first couple of hours, searchers worked independently.
The first organized rescuers to arrive on the scene were the Alaska State Troopers and the Girdwood Fire Department, followed shortly by Chugach Powder Guides, Alaska Mountain Rescue Group, Alaska Search and Rescue Dogs, National Ski Patrol, Mt. Alyeska Pro Patrol, US Forest Service, and Alaska Mountain Safety Center. Several helicopters were on site and were used to transport rescuers to the site. An aerial scene safety assessment was done before putting rescuers on the snow. Nightfall came at about 19:00, and the rescue was called off until daybreak. The site commander felt this was the only way they could gain control of the scene and determine how many people were unaccounted for.
On Monday, roughly 200 people searched the area for more than 12 hours. The bodies of Jodi Combs and Jeff Saunders were found under seven feet of snow by coarse probe lines.
On Tuesday, under deteriorating weather, the search continued for the remaining two victims, again using probe lines and using a snowcat to scrape snow from probable burial areas. Neither man was found.
On Wednesday, the weather went from bad to worse with heavy, wet snowfall and 30 to 40 mph winds. An all-out effort with 450 rescuers proved successful in finding the body of Victor Jones, who was also buried seven feet deep, like several of the other victims.
On Thursday, Friday, and Saturday, about 40 to 50 friends and relatives of the final missing victim, Aaron Arthur, continued to search without results. After that, Arthur’s family asked all searchers to stop because they did not want them to be put at further risk. Arthur’s body was eventually recovered, but no details were provided.
It is interesting to note that several rescue dogs worked the debris area but were ineffective. There were likely several reasons for this—the density of the debris, deep burials of most of the victims, and scent contamination from hundreds of rescuers.
This very large avalanche was triggered by numerous snowmobilers riding on a broad, open, southeast-facing slope. The crown was at an elevation of 2,800 feet and was half a mile wide. The avalanche fell 1,750 feet vertical. Slope angles at the crown varied from 32 to 39 degrees across the wide starting zone; however, one rollover below the crown was measured at 48 to 50 degrees. The slope’s alpha angle was 23.5 to 24 degrees.
The depth of fracture averaged six feet, but at one point it was measured at 7.5 feet. The weak layer was facets that had formed during the clear, cold spell of late January into early February. This layer was 0.25 to 0.3 inches thick.
The debris field was mostly eight to 10 feet deep, but in areas it reached depths of 15 to 20 feet. The avalanche was classified as HS-AMu-R5-D4-O. It likely reached speeds of 80 to 100 mph.
Only four documented avalanches in US history have killed more people than this catastrophic slide in Alaska, where the death toll could have easily been higher. The signs that “something big” could happen were present in the form of three large avalanches that had released in the previous two hours. Most of the people in the area—snowmobilers, skiers, and probably a few snowboarders—had not seen the previous avalanches, and therefore were not aware of how dangerous the snowpack had become.
But some of the victims had their warning with the avalanche that released 15 minutes before the larger fatal avalanche. One group talked it over and decided to make one last climb before packing it in. It was the wrong decision.
The snowpack was primed for big avalanches. A layer of facets had formed more than a month earlier, and this potential weak layer covered a vast area. Then the weak layer got buried by the next storm, and as the storms continued, the mass of slab snow increased its stress on the weak layer. It took only one rider to find the sweet spot— sour spot?—at which point the fracture ripped through the weak layer, spreading across the entire slope within seconds. The weight of the slab and the speed at which it moved brought forces that the human body cannot withstand. Six died; it could have been worse.